Novel Target Designs to Mitigate Hydrodynamic Instabilities Growth in Inertial Confinement Fusion

High density carbon (HDC) ablator is one of the promising candidates toward thermonuclear ignition in inertial confinement fusion (ICF), but it shows the largest ablation front instability growth as compared to other traditional ablator materials. In this Letter, we propose a novel HDC-CH capsule design, opening the way to mitigate the hydrodynamic instabilities by using CH as the outermost ablator layer, while keeping HDC as the main ablator for maintaining the advantage of short laser pulses. The CH layer is completely ablated during the shock transit phase. In the HDC-CH design, it is the first shock reflected from the HDC/CH interface that meets the ablation front first, which reduces the ablation front growth factor by about one order of magnitude at peak implosion velocity due to the Richtmyer-Meshkov and the Rayleigh-Taylor instabilities. Our 2D simulation studies demonstrate convincingly that the ablation front growth factor of the HDC-CH capsule can be significantly reduced at both the end of shock transit phase and the time at peak implosion velocity, as compared to a HDC capsule. This novel HDC-CH capsule not only keeps the main advantage of the HDC ablator, but also has the advantage of low hydrodynamic instabilities, which can provide a larger margin toward ICF ignition. It can be applicable to both indirect-drive and direct-drive targets.

Automated summary

The study introduces a novel HDC-CH capsule design that significantly reduces the ablation front growth factor, thus enhancing the potential for successful ICF ignition.